A test of the national missile defense system failed Monday when an interceptor missile did not launch from its island base in the Pacific Ocean, the military said. It was the second failure in months for the experimental program.
The previous test, on Dec. 15, failed under almost identical circumstances. The target missile launched, but the interceptor did not. Military officials later blamed that failure on fault-tolerance software that was oversensitive to small errors in the flow of data between the missile and a flight computer. The software shut down the launch; officials said they would decrease the sensitivity in future launches.